I plan to stay in academia doing research and teaching after I finish the proposed training. I will either stay in the University of Miami or go to a different university to continue my research in the field of arthritis as a faculty member. My specific research interest is to study the role of tumor suppressor protein and proto-oncogene proteins in the regulation of gene expression of MMPs and TIMPs and in the regulation of proliferation and apoptosis of RA-derived fibroblast-like synoviocytes (FLS). I will continue to work in this direction. The goal of the proposed training is to broaden my knowledge about rheumatic disease, especially the role that MMPs, TIMPs, tumor suppressor protein p53, and proto-oncogene proteins play in RA joint degradation, and to expand my capacity to conduct an independent research program. Through the proposed training, I will gain extensive experience in research planing, research execution, writing manuscripts, budgeting, etc., and new technical skills as well. All of the training I get from these studies will certainly lay a solid foundation for me to conduct independent and productive research in the future. The overall objective of this proposal is to examine the biological effects of the inactivation of tumor suppressor protein p53 on the gene expression of MMPs in fibroblast-like synoviocytes (FLS) and to elucidate the molecular mechanisms underlying such biological effects. The eventual goal of this proposal is to explore and develop a rational means of preventing or reversing the progressive destruction of the joint in RA. In the first aim, we will investigate the detailed mechanism(s) of transcriptional regulation of the gene expression of hMMPl and hMMP13 by wild type and mutant p53 using transient transfection assays combined with other methods such as site specific mutagenesis, and gelshift and footprinting assays. In the second aim, we will investigate the role played by p53 in the regulation of gene expression of other members of the MMP and the tissue inhibitors metalloproteinase (TIMP) families using Northern blot, Western blot and ELISA combined with stable or transient transfection methods. In the last aim, we will examine whether overexpression of p53 mutant, or proto-oncogene protein ras or c- myc by themselves or in combination with p53 mutant, will enhance the ability of FLS to invade and degrade articular cartilage. We shall also investigate whether introduction wt-p53 into the transformed FLS will reverse this process using an in vitro cartilage degradation and invasion assay. The results obtained from these studies will add significantly to the understanding of the pathophysiology of RA. In addition, our knowledge of the molecular mechanisms of regulation of MMPs gene expression will be greatly enhanced by the proposed studies. Once the molecular mechanism addressed in this proposal is clearly defined, it may be possible to exploit the information gained for the development of an effective strategy for RA treatment.